The present invention relates generally to hand machine tools.
More particularly, it relates to a hand machine tool, in particular an electric hand machine tool such as a sword saw, a chain saw, a hedge clipper or the like to be operated by both hands, which has a machine housing with a fixed handle and preferably with an additional handle, wherein a motor and a transmission are arranged in an inner housing surrounded by synthetic shell of the machine housing.
Hand machine tools of the above mentioned general type are known in the art. The European document EP 267 312 discloses a hand machine tool and in particular a sword saw, in which the housing is composed of two synthetic plastic shells surrounding two inner housings coupled with one another. One of the inner housings surrounds the motor and forms a bearing tip for a commutator-side bearing and a lower bearing, while the other inner housing surrounds the transmission with toothed gears and lubricant filling. The known sword saw has relatively compact dimensions and is light, so that a synthetic plastic mounting of the housing is not subjected to substantial deformations either by its own mass or by high clamping moments at the handle during operation with the sword saw. Moreover, the outer forces deforming the synthetic plastic housing are retained remote from the both inner housings of the motor bearings.
The sword saw has no saw blades with plunging-in teeth. It cannot perform plunging-in operation with the sword tip. The operating forces or moments acting on the synthetic plastic housing or the handle are relatively small. The manufacture and mounting of the hand machine tool is however very expensive due to the three housings which must be connected with one another. For a hand machine tool of the next higher weight and power class this construction leads to excessively high mass and inconvenience to handle and therefore is suitable only for hand machine tools with low power, particularly without a plunging-in operation.